This invention relates to an apparatus for transferring heat to food articles and, more particularly, to a novel apparatus particularly adapted for holding previously cooked food articles quite near to a preferred temperature for prolonged time periods, and which can also be employed to initially cook food articles or to complete the cooking of food articles that have been previously partially cooked. In addition, the apparatus can also cool the previously cooked or partially cooked food articles or freeze them.
The novel method of cooking and holding food articles for which the present apparatus is utilized is disclosed in U.S. Pat. Nos. 4,210,675, 4,224,862 and 4,278,697 the contents of which are to be incorporated herein by reference in their entirety.
Briefly, the U.S. Department of Agriculture has long determined that there is considerable danger of spoilage and salmonella (food poisoning bacteria) development in food articles which are held for even short periods of time at temperatures ranging between 40.degree. F. and 145.degree. F. Prior art apparatus utilizing, for example, electrically heated air, steam, etc. have encountered problems in attempting to maintain warm food articles held in the apparatus at temperatures above 140.degree. F. within a temperature range of +5.degree. F. without also causing considerable undesired additional cooking or "overcooking" of them as pointed out in the aforementioned patents. The method comprises storing cooked meat or other food articles in a chamber having closure means intended to be repeatedly and frequently opened and closed, supporting the cooked food articles on support means located within the chamber, forcing a heated liquid heat-transferring medium through radiator means located adjacent to and on opposite sides of the support means, and maintaining the humidity within the chamber above that of the atmosphere outside of the chamber and the temperature above 140.degree. F. and within a temperature range of +5.degree. F. The apparatus disclosed in the aforementioned patents for practicing the aforestated method consisted basically of mounting a plurality of support means in vertical stacked relationship to each other. Each of the support means consists of a plate to which is secured a serpentine coil for transferring the heated fluid. The coils of each support means are connected in series relationship to the pump and the sump containing the heated liquid. The aforedescribed support means it has been discovered is both inefficient and expensive to manufacture. The serial connection of all of the plates with their serpentine coils results in an unacceptably high pressure loss of fluid flowing through the coil and the necessity of using a larger pump. In addition, inefficient heat transfer and poor heat distribution resulted from the prior art design and coil connection. Further, placing the sump and pump on the bottom of the heating chamber inhibits air removal from the circulated fluid. The problems associated with the prior art apparatus are eliminated in the present invention by placing the sump and pump above the vertical stack of the food support means and connecting them substantially in parallel by the use of a unique header system. The support means themselves are also novel and considerably more efficient than those of the prior art. They consist of a plurality of spaced-apart tubular members each having one end thereof connected to a first plenum and the other end connected to a second plenum. The spacing between the tubular members permits visual inspection through the supports for the presence of food product left beneath the supports. The plenums are connected to a header system which serves to reduce the pressure drop across all of the supports enabling the use of a smaller pump and drive motor for the circulated fluid. In addition, to ensure even heat distribution over the entire surface of each support, small orifices are positioned at the entrance to each tubular member to even out the fluid flow through all of the tubular members of each support and prevent the tendency of the fluid velocity to be higher through the extreme tubular members than through those in the middle of the support means.
It is therefore the primary object of the present invention to provide a superior apparatus for thawing, cooking, holding and cooling food articles.
It is another object of the present invention to provide a novel support for pans containing the food articles which more efficiently transfer the heat or cold from the support to the pan resulting in a more even distribution of the heat or cold over the entire surface of the pan.
It is yet another object of the present invention to provide a novel header system for interconnecting a group of vertically stacked pan supports which insures an even supply of heating or cooling fluid for each pan support and permits their easy removal for cleaning or replacement.